The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Typically, optical disk readers can include an objective lens that tracks a data spire of the optical disk. However, due to optical axis misalignment, a laser spot may not focus correctly on the data spire and may result in erroneous detection. Several methods, such as differential push pull (three-beam method) and differential phase detection methods exist to correct the error in the position of the objective lens.